Gentlemen,
Surface 3D visualization gives much better perception in any case as correctly mentioned by dberkholz. It is easy to understand because real objects we used to deal with in life look like surfaces rather than clouds. It is also as easy as the fact that line 2D plot look more understandable as compared to spread points. As many as several thousands points can be nicely visualized as 3D surface. Colors help a lot too as correctly mentioned by dberkholz. For more that 1 MLN points the best is still surface 3D visualization but enhanced with real-time zooming (all directions) and flyby, that is normally no problem with reasonable dedicated multidimensional graphics software package.
For better 3D screen shots you can see this for example:
http://www.sciencegl.com/Stock_market/Stock_market.htm

What matters the most I think is a interactive way to read back the data of the interest in any point of the surfaces and at any time of navigation. Read out such as point position following mouse (XYZ), cross-section (cut), difference between markers, etc.
Something like this
http://www.sciencegl.com/Help_stock/Stock_Market_3D.html